Exercise as immune-based therapy
Richard Jefferys, TAG
Many studies have reported that regular exercise confers health benefits and that, conversely, a sedentary lifestyle is a major risk factor for morbidity and mortality (particularly from cardiovascular disease). In recent years, researchers have begun to look more specifically at the immunological effects of exercise. The scientist Richard Simpson, formerly at Napier University in Edinburgh and now based at the University of Houston in Texas, has pioneered the exploration of the intersection between exercise and immune senescence. [1, 2] This research is potentially relevant to HIV infection because, as reported in some prior blog posts), senescent immune cells – particularly CD8 T cells – accumulate over time and may persist despite antiretroviral therapy. 
Simpson’s recent work suggests that exercise mobilises senescent immune system cells from the tissues into the blood and increases their death by apoptosis;  if confirmed this may offer both a more practical approach to addressing senescence than the idea of physically removing cells, and could also explain some of the positive contributions of exercise to healthy ageing that have been described in the literature.
Exercise may also have a beneficial impact on inflammation, another problem common to both ageing and HIV infection. In Nature Reviews Immunology, Mike Gleeson and colleagues from Loughborough University in the UK review the mechanisms by which exercise may reduce inflammation, and highlight some of the questions that remain to be answered about which mechanisms are most important in producing beneficial health outcomes. 
Finally, in a paper in press at the Journal of the Association of Nurses in AIDS Care, Anella Yahiaoui and colleagues review the literature in an attempt to offer evidence-based exercise recommendations for older individuals with HIV.  They conclude that:
“Combined moderate to vigorous aerobic and resistance exercise for 20-40 minutes, 3 times per week, is safe and effective in older adults and has many benefits to decrease symptom burden, decrease disease progression, and increase quality of life.”
Additional specifics are included in the paper. The authors also recommend the basic ‘Exercise Tips for Older Americans’ offered on the website of the American Heart Association. 
Of interest, a study at EACS in HIV positive patients with high cardiovascular risk, reported that an intensive and multidisciplinary intervention on lifestyle led to a significant improvement in lipid profile, quitting smoking and Framingham risk score. 
Source: TAG basic science blog (15 August 2011).
- Simpson RJ. Aging, persistent viral infections, and immunosenescence: can exercise “make space”?
- Simpson RJ et al. Senescent phenotypes and telomere lengths of peripheral blood T-cells mobilized by acute exercise in humans. Exerc Immunol Rev. 2010;16:40-55.
- Spielmann G et al. Aerobic fitness is associated with lower proportions of senescent blood T-cells in man. Brain Behav Immun. 2011 Jul 19. [Epub ahead of print].
- Gleeson M et al. The anti-inflammatory effects of exercise: mechanisms and implications for the prevention and treatment of disease. Nat Rev Immunol. 2011 Aug 5. doi: 10.1038/nri3041. [Epub ahead of print]
- Yahiaoui A et al. Development of evidence-based exercise recommendations for older HIV-infected patients. J Assoc Nurses AIDS Care. 2011 Jul 29. [Epub ahead of print]
- Saumoy M et al. Efficacy of an Intensive and Multidisciplinary Intervention on Lifestyle in Cardiovascular Risk and Metabolic Variables in HIV-infected Patients: 96-week Results. 13th EACS, 12?15 October 2011, Belgrade. Abstract PE9.5/4.